1. Field of the Invention
The present invention relates generally to tail gate devices of the type used in heavy hauling applications and more particularly to an improved counterbalanced dump gate construction.
2. Description of the Prior Art
Dump bodies have long been provided with pivotable tail gate constructions to facilitate removal of carried materials by merely raising the front end of the body and allowing the carried material to slide from the rear past a tail gate which is either pivoted at the top and latched at the bottom, or pivoted at the bottom and latched at the top, or both. An early version of the latter is disclosed in the U.S. Pat. No. 1,371,036 to D. E. Le Force.
Very early on, it was recognized that when the gate was opened by pivoting it about its bottom edge, the very large and heavy gate was apt to fall rapidly with the likelihood of injuring workers or striking an object and causing damage to either the gate or the object struck or both. In order to avoid this problem, spring loading mechanisms such as that disclosed in the U.S. Pat. No. 514,076 to C. Hotz, were provided to counterbalance the weight of the gate. The problem with such constructions however, was that if such means were utilized, it was difficult and perhaps even impractical to allow the gate to be alternatively pivoted from the top because to do so meant dismantling of the counterbalancing apparatus.
Subsequently, a counterbalancing structure was disclosed in U.S. Pat. No. 2,260,504 to E. R. Barrett which included a latching structure at the bottom of the gate that allowed the gate to be pivoted from the top, and included a spring loaded counterbalancing mechanism mounted in the side walls of the truck body with means for engaging the lower pivot pins of the gate in such a manner that when the gate was pivoted at its bottom, the counterbalancing forces were applied to the lower portion of the gate allowing it to be safely rotated about its pivot pins into its open position. The problem with such structure however, was that it provided a rather complicated mechanism for engaging the lower pivot pins of the gate and required modification of the dump body to accommodate the counterbalancing spring mechanism. Furthermore, since the bottom latching mechanism was actuated from the front of the truck, it was not unusual that a worker closing or cleaning debris from the gate had his fingers impaired in the process.